This research project is concerned with the functional role of the trigeminal (V) spinal subnucleus caudalis in the processing of pain information. Our long term goal is to determine how pain information is transmitted and regulated in the central nervous system. The specific goal of this proposal is to examine primary afferent-evoked synaptic responses and the action potential in trigeminothalamic neurons in thin medulla slices. The ionic currents and single channel activities of trigeminothalamic neurons will be measured using patch clamp recording techniques. The information obtained will enhance our understanding of the role that trigeminal system has in processing pain-related messages and will facilitate the designing of the therapy for the treatment of orofacial pain.